This invention relates to the detection of proteins by the utilization of the phenomenon by which such proteins interact specifically either immunologically or non-immunologically.
The preparation and use of protein-coated droplets dispersed in a tissue culture medium for growing cells is described and claimed in the U.S. patent application Ser. No. 443,311--Giaever and Keese, filed Nov. 23, 1982. This application is incorporated by reference.
The use of small magnetic particles coated with a protein that will interact specifically with a select protein in order to separate such select protein from a solution is disclosed in U.S. Pat. No. 4,018,886--Giaever. Also, the use of small magnetic particles coated with an antibody layer for sorting out and separating select viruses, bacteria and other cells from multi-cell, bacteria or virus populations is disclosed in U.S. Pat. No. 3,970,518--Giaever.
The use of inert molecules as "spacers" for molecules of interest is described in pending U.S. patent application Ser. No. 358,219--Giaever, filed Mar. 15, 1982 and assigned to the assignee of the instant application.
A common test for pregnancy involves coating small polystyrene latex spheres with the hormone, human chorionic gonadotropin (HCG). When a woman becomes pregnant, the level of HCG in the urine increases significantly. This is an indirect test in which a quantity (as determined by titer by an established procedure) of antibodies to HCG is added to a sample of female urine and is allowed to incubate for from about 5 to about 10 minutes therein. Next, HCG-covered latex spheres are mixed with the urine and the mix is allowed to incubate for from about 5 to about 10 minutes. If agglutination of the spheres takes place, the urine does not contain HCG to the level establishing a pregnant condition; if the spheres remain in single suspension, HCG was present beyond that level.
These tests can be generalized to detect any antigen or antibody. The fact of agglutination preferably should be visible to the ordinary observer.
U.S. patent application Ser. No. (665,902)--Giaever and Keese, filed , Oct. 29, 1984, discloses and claims an invention in which an emulsion (in which an aqueous medium contains small dispersed liquid droplets coated with a protein that will interact specifically with a select protein) is mixed with a liquid sample, time is allowed for interaction to occur and then the mixture is exposed to a tagged antibody specific to the select protein. After an appropriate hold time the emulsion is broken and the protein that previously covered the disperse droplets becomes concentrated at the interface between the two continuous phases. The interface is checked for the presence of the tagged antibodies to establish the presence or absence of the select protein. This application is assigned to the assignee of this invention and is incorporated by reference.